The present invention relates to the field of medical spectroscopy and more specifically to the field of mounting sensors on a patient for use in spectroscopy.
The use of spectroscopy in medical condition diagnosis has become commonplace. Typically, light is placed on the surface of tissue in one location and transmitted or scattered light is collected from the tissue in another location. A spectral analysis of the collected light is then performed and the results are compared to stored information about spectral profiles of tissue having known conditions. From this comparison, the condition of the tissue under study may be determined.
The light to be transmitted into the tissue is typically placed on the tissue through use of an optical head. The same optical head may be used to collect the light. Some spectroscopy systems allow for collection of light that passes through tissue and therefore one optical head is used for light transmission while a second optical head is used for collection.
The optical head may be held directly on the tissue by a doctor, nurse or technician, it may be directly taped or strapped into place, an external structure may hold it in place or it may be held securely in place through a patient interface. A patient interface is a specially designed structure that will typically hold the optical head within its structure and includes an adhesive, suction, compressive, strapping, or other (e.g. glove like) structures to hold the patient interface securely to the patient's tissue. Some examples of patient interfaces are shown in U.S. Pat. Nos. 4,223,680, 4,537,197, 4,653,498 (the “New” patent), 4,817,623, 4,825,879 (the “Tan” patent), 4,830,014 (the “Goodman” patent), 4,865,038 (the “Rich” patent), 4,964,408 (the “Hink” patent), 5,094,240, 5,111,817 (the “Clark” patent), 5,224,478, 5,267,563, 5,402,777, 5,584,296, 5,879,373 and 6,381,489.
It has been found that performing blood spectroscopy on the fingers allows for access to a significant quantity of blood vessels that are near the surface of the skin. Accordingly, a number of patents have been directed to such patient interfaces mountable on a finger, such as the New, Tan, Goodman, Rich, Hink and Clark patents.
A problem with spectroscopy of fingers is that the patient interfaces or the attachment straps tend to wrap entirely around the finger. Blood flow to the finger can be thereby restricted and this can affect the accuracy of the spectroscopy.
Further, some locations on the body present more blood vessels near the surface than others. Even within a short range of a location that provides a reasonable level of blood vessels for measurement, a better location may exist. However, the prior art suffers from an inability to relocate the sensor easily once the sensor has been affixed to the tissue.